544x480, etc: changing recording resolution

[mccg]

Hi folks,

I've just installed TivoWeb 1.9.4 beta 3, and the resource editor appears to work - It actualy gives me some values to edit now!

I have adjusted the CATVBestResolution, but it was getting late, so will see what it looks like tonight.
(I do know you have to hit enter after each change - I saw a confirmation screen that the setting had been changed. I then went back and hit the "Update Resources" link and rebooted the TiVo)

Cheers,
Mike

[bato]

Originally posted by artships


What I get from my Sony SA v3.0, though, is never 720x480. TiVo is connected to my satellite receiver via S-Video and the RCA-plug coax for left and right audio.

...

John

What I read at vcdhelp is that S-Video resolution is in fact 352x480, so I guess if we capture at 352x480 at a higher bitrate we can get the video almost as good as the source.

[mccg]

Hi bato,

You've got that wong....
I haven't been to the vcdhelp site, so you may have misunderstood what they have written.
Maybe SVCD is 352. S-video certainly isn't

PAL TV resolution is about 768 (as they don't use pixels, you can't really talk about resolution)
S-VHS has about 625 horizontal (which is why the logo has a small 625 in it)
VHS (IIRC) is about 425.

"PAL" DVD's are usually 720 (I know they are not PAL encoded, but they are designed for use on PAL TVs)


I have managed to change the resolution, using the "Bitrates" section of TivoWeb 1.9.4 B3. Changing just the AltBitrates doesn't have any effect.
But, it isn't useable, as the picture gets shifted about 2 inches to the left, so I get a big black bar on the right, with a green stripe at the far right, and the left hand edge is chopped off, eg: on BBC News 24 (widescreen) the clock, which is in the 4x3 safe area, is actually half off the screen!

I have gone back to resolution 2 (480) :-(

Cheers,
Mike

[trekkerj]

I have a Philips SA with 3.0. I tried these settings in TiVoWeb, made sure they were set, and recording something with Basic Quality. It was still 480x480 even with Resolution set to 0. Does this no longer work with 3.0? I checked my System information which now says that I have 36 hours record time for both Best and Basic. But the file pulled is still not 720.

[laserfan]

Originally posted by trekkerj
...I tried these settings...made sure they were set...

You need to check again, cuz they do indeed work. I suspect for some of your changes you didn't hit "Enter" after each one (obviously some "took" as your Record times changed).

[trekkerj]

I indeed hit enter and double and triple checked my settings. They are all as you described. Nonetheless, no matter what I do, I always get 480x480.

RecordQualityBasic 75
CATVBasicVBRBitrate 5215000
CATVBasicMAXBitrate 5960000
CATVBasicResolution 0

This is directly from tivoweb. I did this for both pages (bitrates, and alt bit rates), hitting enter after each one and then update resources, then reboot tivo. The system information page indicates I made a change to basic quality. No dice.

[artships]

Originally posted by trekkerj
no matter what I do, I always get 480x480.

RecordQualityBasic 75
CATVBasicVBRBitrate 5215000
CATVBasicMAXBitrate 5960000
CATVBasicResolution 0

Try setting RecordQualityBasic to 65.

As I posted earlier, even at 65 watching while it's recording produces audio glitches (that do NOT show-up on the recordings), giving me the impression that tivo has a hard time keeping-up at 65. You may be experiencing tivo as it overrides setting combinations it finds too taxing.

John

[laserfan]

trekkerj, what are you using to verify that your programs are indeed being recorded at 480x480? I'm curious; I've used MPEGPROP and DVDPatcher and one of my players (DV Station) shows the resolution. I'm wondering what others are using to inspect their file properties.

A couple of my apps do a good job at HIDING what the properties truly are also (i.e. misrepresenting them) e.g. Mediacruise.

[khmann]

Originally posted by trekkerj
I indeed hit enter and double and triple checked my settings. They are all as you described. Nonetheless, no matter what I do, I always get 480x480.

RecordQualityBasic 75
CATVBasicVBRBitrate 5215000
CATVBasicMAXBitrate 5960000
CATVBasicResolution 0

I'm guessing that what's happening to you is the 'RecordQualityBasic' is the same as your 'RecordQualityMedium'. What I've found from my tests is that the 'Quality' factor is nothing more than a numerical value the TiVo uses internally to keep track of the various bitrates. ie- it does not impact the recorded video at all.

I have verified this by recording a very high bitrate DVD sequence using VBR at both quality 90 and quality 5. Analyzing the MPEG video with 'BitView' shows no difference in the bitrate/quantization.

If you want a smaller file, reduce the VBRBitrate- the actual numerical value seems to have little to do with reality- I think what happens is that somehow the VBRBitrate:MAXBitrate ratio is used to assign a minimum Q value to the encoder.

In my opinion, 5.8M MAX is _way_ too low for 720x480, but YMMV. Also note that for some reason on my box, CBR starts screwing up above about 7.5M. Try turning on VBR (enable 'save disk space'), and crank the MAX bitrate up.

I'm able to record and playback 9.8M MAX/9M VBR material simultaneously with no glitches on a 2.51 SA with a 7200RPM drive.

[trekkerj]

That's good information. Alhough I have a 5400 RPM drive in there, so I may keep the bitrate the same as the best quality settings and enable VBR. I will try changing the RecordQualityBasic to 65 and see if that gives me 720.

I use DVD patcher to get the res, but what it really important is Spruce DVD which won't accept the video if it is 480x480.

[trekkerj]

I changed the RecordQualityBasic to 65. Now tivo won't let me record at BASIC anymore. I try basic and it records at Medium. What is going on here?

[khmann]

you've screwed up all the record modes and the TiVo doesn't know what to do :)

the defaults are:
best=100
high=75
medium=40
basic=0

--------

When you tell the TiVo 'Basic', it's looking for the lowest 'Quality' # it can find. in your case I'm assuming that's 40... which equals Medium by default.

be aware that I may have absolutely no idea what I'm talking about.

[trekkerj]

You may be right. OK, so I changed Medium Quality to 70. and kept Basic at 65. Now I finally get 720x480. I am using the same bitrates as Best Quality. This is about 40MB/minute, which is under 5GB per 2 hours. I would like to make it so that 2 hours fits on a standard DVD-R. Perhaps if I turn on Save Disk Space, this will make the difference? I will have to find a movie to test this out on.

[laserfan]

I think khmann may be right about the Quality numbers. I had at one point set them all to 100, and found that Tivo thought they were all the same i.e. it predicted that 'Best' to 'Basic' would all result in the same recording time capacity of my Tivo. So I put them back and have decided if they affect recordings at all it is probably in VBR mode, but...

I have not liked at all the VBR mode (Save Disk Space--I get blockiness & pixellation too often) and am gravitating towards the following settings at CBR:
Best, Res 0, 720x480, Quality 100, CBR 5800kbps, ~2633Mb/hour
High, Res 2, 480x480, Quality 75, CBR 3500kbps, ~1622Mb/hour
Medium, Res 2, 480x480, Quality 40, CBR 2600kbps, ~1227Mb/hour
Basic, Res 1, 352x480, Quality 0, CBR 1470kbps, ~730 Mb/hour

Note that Best and Basic will work on DVDs, Basic may also fit on a single CD (haven't tried that yet). Medium works as an SVCD on my player (bitrate needs to be 2600kbps or less or I get audio stuttering). High can get a couple hour movie on one DVD-R. I'm finding/deciding that Best I use NOT for recordings I want to save to disc, but rather for anything I'm going to watch and delete. I don't think the bitrate will even allow a 2hr movie on a DVD?

Anyway I'm finding I use Medium for most stuff and High for only the very best quality programs off digital cable. Note however that most of what I'm saving is music programming i.e. 'live' performances of favorite artists/songs so audio comes first and video quality comes second (but they do look good as there is not a lot of motion in them so lower bitrates work well).

[trekkerj]

Now if you set resolution to 0 on BEST quality, do you notice problems during Live TV?

I tried 4200KBps VBR at 720x480, recorded a 2 hr 20min movie and the total file size was 3660 MB. I'm thinking to up it to 4800 and a constant bit rate.

Many of these channels are digital from my cable company. I expect they use a low bitrate to fit everything into the space available. Perhaps I will try to get specific numbers. Doesn't make sense to record at a higher bitrate than I am getting the video at.